Specs of a stock Amp for Sub? 2001 GMC Yukon XL

I'm just curious what the specs are of the stock amp that runs the factory subwoofer. Anyone have any idea? If it's respectable enough to run a new quality replacement 8" sub, that's what I'm going to do. Why you ask? Because I'm trying to save $$$ and up grade the sound a bit. I have the CDA-9884 Alpine head unit, SPR-17c 6.5" Alpine speakers in the 4 doors. Just want a little cleaner bass and not comprimise cargo space. yes, I'm getting old. Any help would be greatly appreciated. Yes, I've called a GM dealer and it amazes me that they can't answer my question. That info is somewhere!